In general, most religious orders have an eight-year period of formation before taking "final" or "perpetual" vows. That means that most members of religious orders have eight years to discern whether or not God is calling them to a particular way of life.
However, for a member of the Society of Jesus (Jesuits), that period of formation can take up to 12 years (or more). It all depends on what state of life the man is in and if he has any previous theological education.
Novitiate
As with most religious orders, there is a two-year novitiate, where a novice is given the chance to experience life as a Jesuit and test God's call.
First Studies
After two years, typically a novice will take first vows, which is the first major step into committing to the Society of Jesus. During this time, Jesuits will attend university to either complete their Bachelor's degree, or to pursue graduate studies in philosophy or theology.
Depending on their prior education, this could take four years or more to complete.
Regency
After his studies are complete, a Jesuit will complete a three-year Regency program, where he will be sent to one of a variety of apostolates or ministries around the world.
Theological Studies
At the completion of Regency, a Jesuit will complete their theological studies, which is often another three years of study, before becoming ordained a priest.
Tertianship
After being ordained a priest, a Jesuit still has about 3 to 5 years remaining before he professes his final vows. What is unique about Jesuits is that a man could be ordained a priest before becoming a fully professed Jesuit.
